Agglomerated particles of finely divided polymers which are water-soluble or capable of swelling in water and contain ammonium carboxylate groups

Abstract

Agglomerated polymer particles of finely divided, water-soluble or water-swellable polymers containing ammonium carboxylate groups are prepared by azeotropic removal of water from water-in-oil emulsions of the water-soluble or water-swellable polymers which contain ammonium carboxylate groups in the presence of from 0.1 to 40% by weight, based on the polymers, of polyalkylene glycols which have an agglomerating effect and which are obtainable by an addition reaction of C 2 -C 4 -alkylene oxides with alcohols, phenols, amines or carboxylic acids and contain at least two polymerized alkylene oxide units and additionally of from 0.1 to 20% by weight, based on the polymers, of protective colloids which are obtainable by free radical copolymerization of C 8 -C 40 -monoolefins with monoethylenically unsaturated C 4 -C 6 -dicarboxylic anhydrides by a mass polymerization method at from 80 to 300° C. to give copolymers having molecular weights of from 500 to 20,000 g/mol, and said agglomerated polymer particles are used as thickeners for textile pigment print pastes.

We claim:  
     
       1. A process for the preparation of agglomerated polymer particles of finely divided, water-soluble or water-swellable polymer which contain ammonium carboxylate groups and at least 50% by weight of a monethylenically unsaturated carboxylic acid as polymerized units, the agglomerated particles having a mean particle diameter of from 20 to 2500 μm and consisting of primary particles having a mean particle diameter of from 0.1 to 15 μm, which are obtained by polymerization of a monomer composition comprising at least 50% by weight of monethylenically unsaturated carboxylic acids and, optionally, other monoethylenically unsaturated monomers and, optionally, a crosslinking agent by a water-in-oil polymerization method, comprising 
       azeotropically removing at least 70% of the water from water-in-oil emulsions of water-soluble or water-swellable polymers which contain ammonium carboxylate groups and have a mean particle diameter of from 0.1 to 15 μm, in the presence of  
       1) from 0.1 to 40% by weight, based on the polymers, of polyalkylene glycols which have an agglomerating effect and which  
       a) are obtained by an addition reaction of C 2 -C 4 -alkylene oxides with alcohols, phenols, amines or carboxylic acids and  
       b) contain at least two polymerized alkylene oxide units, and  
       2) from 0.1 to 20% by weight, based on the polymers, of protective colloids which are obtained by free radical copolymerization of  
       a) C 8 -C 40 -monoolefins with  
       b) monoethylenically unsaturated C4-C6-dicarboxylic anhydrides  
       by a mass polymerization method at from 80 to 300° C. to produce copolymers having molecular weights of from 500 to 20,000 g/mol, and containing from 40 to 60 mol % of polymerized monoolefins and from 60 to 40 mol % of polymerized monoethylenically unsaturated carboxylic acids, it being possible for the copolymers containing anhydride groups to be hydrolyzed to copolymers containing acid groups or to be modified by reaction with alcohols, alkali metal bases, ammonia or amines; and  
       isolating the agglomerated polymer particles.  
     
     
       2. A process for the preparation of agglomerated polymer particles as claimed in  claim 1 , wherein, in the polymerization, acrylic acid, methacrylic acid or a mixture of acrylic acid and methacrylic acid is used as the water-soluble monomers and methylenebisacrylamide is used as the crosslinking agent, and the carboxylic acids may be present in a form partially or completely neutralized with ammonia. 
     
     
       3. A process as claimed in  claim 1 , wherein, in the copolymerization, a mixture of acrylic acid and acrylamide and/or methacrylamide or a mixture of methacrylic acid and acrylamide and/or methacrylamide is used as the water-soluble monomers and methylenebisacrylamide is used as the crosslinking agent.